Pinholes occur as a result of no degreasing or improper degreasing. Dust, lint, oils, and chemicals on your screen will cause pinholes. Pinholes are small transparent dots that are present on printed garments and appear for the first time on your screens after exposure. They open up in our emulsion and essentially destroy the crisp and clear printed garment. Overcoming the challenge that pinholes create will save your shop time and money.
1. Improper Degreasing
2. Mesh Contamination
3. Poor Emulsion or Particles in Emulsion
4. Improperly Prepared Emulsion
5. Dust, Lint, Oils, and Chemicals
6. Poor Drying After Degreasing or Before Exposure
7. Coating Completed Incorrectly
8. Improper Exposure Time
How to Avoid Pinholes:
Properly executing each step in the screen printing process will enable you to avoid pinholes.
1. Screen Degreasing:
Screen degreasing is one of the major steps that if done incorrectly will cause pinholes. Read our ‘7 Step Guide for Proper Screen Degreasing’
2. Mesh Contamination:
Ensure you have thoroughly degreased and rinsed the screens even if the mesh is new to avoid mesh contamination. Chemicals, dirt, and lubricants must be rinsed. Store the screens properly. If screens are kept in the open, there is more opportunity for them to be contaminated. Clean and dry the screen properly. Keep screens in a drying cabinet to avoid contamination. Tap water tends to have a high iron content, so distilled water is recommended. Take your time while coating the screen with emulsion to ensure quality coverage. Guarantee the emulsion is dry so you do not have problems with underexposure.
1. Blockout Pen- This is a water soluble pen that can touch up any pinhole quickly and drys within 30 seconds. These pens are great for on or off the press touch ups and can easily fix the garment to keep production going in a quick, timely matter.
2. Blockout Liquid- This is a water soluble liquid that is made to cover up pinholes as well as emulsion breakdowns.
3. Tape- Tape over pinholes. The only issue is that the squeegee could pull the tape up, exposing the garment instead of the ink.
4. Finger- Dip your finger with emulsion and tap it onto the pinhole. Place the screen in the sunlight to let dry. Wash emulsion off your finger.